Fuel cell and system for supplying electrolyte thereto with wick feed

• US 4,463,068 A
• Filed: 09/30/1982
• Issued: 07/31/1984
• Est. Priority Date: 09/30/1982
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Department Of Energy
• Original Assignee: Engelhard Corporation (BASF SE)
• Inventors: Feigenbaum, Haim, Kaufman, Arthur, Cohn, J. Gunther
• Primary Examiner(s): Skapars, Anthony
• Application Number:
  US06/430,155
• Time in Patent Office: 670 Days
• Field of Search: 429/34, 429/38, 429/39, 429/41, 429/13, 429/51, 429/80, 429/72, 429/44
• US Class Current: 429/451
• CPC Class Codes: H01M 50/70 Arrangements for stirring or circulating the electrolyte
• CPC Class Codes: H01M 8/04283 Supply means of electrolyte to or in matrix-fuel cells
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: H01M 8/2484 characterised by external manifolds
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An electrolyte distribution and supply system for use with a fuel cell having a means for drawing electrolyte therein is formed by a set of containers of electrolyte joined to respective fuel cells in a stack of such cells. The electrolyte is separately stored so as to provide for electrical isolation between electrolytes of the individual cells of the stack. Individual storage compartments are coupled by tubes containing wicking fibers, the ends of the respective tubes terminating on the means for drawing electrolyte in each of the respective fuel cells. Each tube is heat shrunk to tightly bind the fibers therein.

Claims

1. A system for supplying electrolyte to fuel cells in a stack of fuel cells comprising:

(a) means for storing electrolyte externally to said fuel cells, an individual one of said cells including an electrolyte matrix means for drawing electrolyte;

(b) means for conducting electrolyte from said storing means to the electrolyte matrix means in each of said cells, said conducting means including a wicking medium; and

(c) means for maintaining a predetermined hydrostatic pressure of electrolyte at said conducting means.

2. A system according to claim 1 wherein said storing means stores electrolyte separately for each of said fuel cells of said stack and wherein said system is configured to provide electrical isolation among the separately stored electrolytes for each of said cells.

3. A system according to claim 2 wherein said storing means is in the form of a set of troughs having open mouths, each of said troughs being filled by applying electrolyte through its mouth until the trough overflows so as to maintain a predetermined depth and hydrostatic pressure within the storing means.

4. A system according to claim 3 wherein said conducting means comprises a set of tubes having wicking fibers therein, each of said tubes being coupled from individual compartments of said storing means to respective ones of said fuel cells.

5. A system according to claim 4 wherein said tubes are fabricated of heat shrinkable plastic and said fibers are of carbon, said plastic of said tubes being heat shrunk after insertion of said fibers therein to tightly bind said particles together.

6. The system according to claim 4 wherein said wicking fibers comprise graphite fibers.

7. The system according to claim 1 wherein said storing means stores electrolyte for a group of two or more of said fuel cells in said stack.

8. The system according to claim 7 wherein said storing means stores electrolyte separately for each of said groups of fuel cells and wherein said system is configured to provide electrical isolation among the separately stored electrolytes for each of said group.

9. A system according to claims 2 or 7 wherein the fuel cells in the stack have electrodes at which electrochemical reactions take place between fluidic reactants and the electrolyte and wherein the electrolyte matrix means comprises:

(a) first and second permeable layers arranged in a laminated format, at least one of which is electrically insulating;

(b) said first layer having relatively large pores for providing electrolyte in an ion conducting path between said electrodes; and

(c) said second layer having relatively small pores for drawing electrolyte from said first layer, said second layer being positioned contiguous to an interaction surface of one of said electrodes for supplying electrolyte to the electro-chemical reaction at said one electrode.

10. A system according to claim 9 wherein said electrolyte supporting structure comprises a third permeable layer arranged in a laminated format with said first and said second layers, said third layer having relatively small pores as compared to the pores of said first layer for drawing.

11. A system according to claims 1 or 4 wherein said wicking medium extends into and substantially across the electrolyte matrix means so as to distribute electrolyte directly to a larger portion of said matrix.

12. A system for supplying electrolyte to fuel cells in a stack of fuel cells comprising:

(a) means for storing electrolyte externally to said fuel cells, an individual one of said cells including an electrolyte matrix means for drawing electrolyte; and

(b) means for conducting electrolyte from said storing means to the electrolyte matrix means in each of said cells said conducting means including a wicking medium.